Hi David,
I tried with my Oracle 11 and I still don't see any problem. From your image it looks like there should be some problem with some datatype which are you using. Can you confirm that it happen on more tables with different datatypes in columns (some simple table with few columns would be great). If you have still problem also on other tables then I would like to ask if you can create Support Bundle (in Help -> Support Bundle) and send it to me.